Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * User-space Probes (UProbes) for sparc
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright (C) 2013 Oracle Inc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * Authors:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *	Jose E. Marchesi <jose.marchesi@oracle.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  *	Eric Saint Etienne <eric.saint.etienne@oracle.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/highmem.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/uprobes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/sched.h> /* For struct task_struct */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/kdebug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <asm/cacheflush.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) /* Compute the address of the breakpoint instruction and return it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  * Note that uprobe_get_swbp_addr is defined as a weak symbol in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  * kernel/events/uprobe.c.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	return instruction_pointer(regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) static void copy_to_page(struct page *page, unsigned long vaddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 			 const void *src, int len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	void *kaddr = kmap_atomic(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 	kunmap_atomic(kaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) /* Fill in the xol area with the probed instruction followed by the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41)  * single-step trap.  Some fixups in the copied instruction are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42)  * performed at this point.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44)  * Note that uprobe_xol_copy is defined as a weak symbol in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45)  * kernel/events/uprobe.c.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 			   void *src, unsigned long len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	const u32 stp_insn = UPROBE_STP_INSN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	u32 insn = *(u32 *) src;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	/* Branches annulling their delay slot must be fixed to not do
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	 * so.  Clearing the annul bit on these instructions we can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	 * sure the single-step breakpoint in the XOL slot will be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	 * executed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	u32 op = (insn >> 30) & 0x3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	u32 op2 = (insn >> 22) & 0x7;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	if (op == 0 &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	    (op2 == 1 || op2 == 2 || op2 == 3 || op2 == 5 || op2 == 6) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	    (insn & ANNUL_BIT) == ANNUL_BIT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 		insn &= ~ANNUL_BIT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	copy_to_page(page, vaddr, &insn, len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	copy_to_page(page, vaddr+len, &stp_insn, 4);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) /* Instruction analysis/validity.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74)  * This function returns 0 on success or a -ve number on error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 			     struct mm_struct *mm, unsigned long addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	/* Any unsupported instruction?  Then return -EINVAL  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) /* If INSN is a relative control transfer instruction, return the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84)  * corrected branch destination value.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86)  * Note that regs->tpc and regs->tnpc still hold the values of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87)  * program counters at the time of the single-step trap due to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88)  * execution of the UPROBE_STP_INSN at utask->xol_vaddr + 4.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) static unsigned long relbranch_fixup(u32 insn, struct uprobe_task *utask,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 				     struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	/* Branch not taken, no mods necessary.  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	if (regs->tnpc == regs->tpc + 0x4UL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 		return utask->autask.saved_tnpc + 0x4UL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	/* The three cases are call, branch w/prediction,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	 * and traditional branch.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	if ((insn & 0xc0000000) == 0x40000000 ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	    (insn & 0xc1c00000) == 0x00400000 ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 	    (insn & 0xc1c00000) == 0x00800000) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 		unsigned long real_pc = (unsigned long) utask->vaddr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 		unsigned long ixol_addr = utask->xol_vaddr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 		/* The instruction did all the work for us
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 		 * already, just apply the offset to the correct
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 		 * instruction location.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		return (real_pc + (regs->tnpc - ixol_addr));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	/* It is jmpl or some other absolute PC modification instruction,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	 * leave NPC as-is.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	return regs->tnpc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) /* If INSN is an instruction which writes its PC location
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)  * into a destination register, fix that up.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) static int retpc_fixup(struct pt_regs *regs, u32 insn,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 		       unsigned long real_pc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	unsigned long *slot = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	int rc = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	/* Simplest case is 'call', which always uses %o7 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	if ((insn & 0xc0000000) == 0x40000000)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		slot = &regs->u_regs[UREG_I7];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	/* 'jmpl' encodes the register inside of the opcode */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	if ((insn & 0xc1f80000) == 0x81c00000) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 		unsigned long rd = ((insn >> 25) & 0x1f);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		if (rd <= 15) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 			slot = &regs->u_regs[rd];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 			unsigned long fp = regs->u_regs[UREG_FP];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 			/* Hard case, it goes onto the stack. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 			flushw_all();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 			rd -= 16;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 			if (test_thread_64bit_stack(fp)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 				unsigned long __user *uslot =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 			(unsigned long __user *) (fp + STACK_BIAS) + rd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 				rc = __put_user(real_pc, uslot);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 			} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 				unsigned int __user *uslot = (unsigned int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 						__user *) fp + rd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 				rc = __put_user((u32) real_pc, uslot);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	if (slot != NULL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 		*slot = real_pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) /* Single-stepping can be avoided for certain instructions: NOPs and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162)  * instructions that can be emulated.  This function determines
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163)  * whether the instruction where the uprobe is installed falls in one
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164)  * of these cases and emulates it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166)  * This function returns true if the single-stepping can be skipped,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167)  * false otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	/* We currently only emulate NOP instructions.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	if (auprobe->ixol == (1 << 24)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 		regs->tnpc += 4;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 		regs->tpc += 4;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 		return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) /* Prepare to execute out of line.  At this point
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184)  * current->utask->xol_vaddr points to an allocated XOL slot properly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185)  * initialized with the original instruction and the single-stepping
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186)  * trap instruction.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188)  * This function returns 0 on success, any other number on error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	struct uprobe_task *utask = current->utask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	struct arch_uprobe_task *autask = &current->utask->autask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	/* Save the current program counters so they can be restored
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	 * later.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 	autask->saved_tpc = regs->tpc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 	autask->saved_tnpc = regs->tnpc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	/* Adjust PC and NPC so the first instruction in the XOL slot
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	 * will be executed by the user task.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	instruction_pointer_set(regs, utask->xol_vaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) /* Prepare to resume execution after the single-step.  Called after
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210)  * single-stepping. To avoid the SMP problems that can occur when we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211)  * temporarily put back the original opcode to single-step, we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212)  * single-stepped a copy of the instruction.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214)  * This function returns 0 on success, any other number on error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	struct uprobe_task *utask = current->utask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	struct arch_uprobe_task *autask = &utask->autask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	u32 insn = auprobe->ixol;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	int rc = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	if (utask->state == UTASK_SSTEP_ACK) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 		regs->tnpc = relbranch_fixup(insn, utask, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		regs->tpc = autask->saved_tnpc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 		rc =  retpc_fixup(regs, insn, (unsigned long) utask->vaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 		regs->tnpc = utask->vaddr+4;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 		regs->tpc = autask->saved_tnpc+4;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	return rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) /* Handler for uprobe traps.  This is called from the traps table and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235)  * triggers the proper die notification.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) asmlinkage void uprobe_trap(struct pt_regs *regs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 			    unsigned long trap_level)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	BUG_ON(trap_level != 0x173 && trap_level != 0x174);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 	/* We are only interested in user-mode code.  Uprobe traps
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 	 * shall not be present in kernel code.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	if (!user_mode(regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 		local_irq_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 		bad_trap(regs, trap_level);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	/* trap_level == 0x173 --> ta 0x73
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	 * trap_level == 0x174 --> ta 0x74
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	if (notify_die((trap_level == 0x173) ? DIE_BPT : DIE_SSTEP,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 				(trap_level == 0x173) ? "bpt" : "sstep",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 				regs, 0, trap_level, SIGTRAP) != NOTIFY_STOP)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 		bad_trap(regs, trap_level);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) /* Callback routine for handling die notifications.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) int arch_uprobe_exception_notify(struct notifier_block *self,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 				 unsigned long val, void *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	int ret = NOTIFY_DONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 	struct die_args *args = (struct die_args *)data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	/* We are only interested in userspace traps */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	if (args->regs && !user_mode(args->regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 		return NOTIFY_DONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 	switch (val) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 	case DIE_BPT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 		if (uprobe_pre_sstep_notifier(args->regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 			ret = NOTIFY_STOP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	case DIE_SSTEP:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 		if (uprobe_post_sstep_notifier(args->regs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 			ret = NOTIFY_STOP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) /* This function gets called when a XOL instruction either gets
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290)  * trapped or the thread has a fatal signal, so reset the instruction
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291)  * pointer to its probed address.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	struct uprobe_task *utask = current->utask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 	instruction_pointer_set(regs, utask->vaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) /* If xol insn itself traps and generates a signal(Say,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301)  * SIGILL/SIGSEGV/etc), then detect the case where a singlestepped
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302)  * instruction jumps back to its own address.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) bool arch_uprobe_xol_was_trapped(struct task_struct *t)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 	return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) unsigned long
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 				  struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	unsigned long orig_ret_vaddr = regs->u_regs[UREG_I7];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 	regs->u_regs[UREG_I7] = trampoline_vaddr-8;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	return orig_ret_vaddr + 8;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) }